was one of the first programmatic efforts at interactive visualization and provided an enumeration of the types of input humans provide. People can:
#Pick some part of an existing visual representation;
#Locate a point of interest (which may not have an existing representation);
#Stroke a path;
#Choose an option from a list of options;
#Valuate by inputting a number; and
#Write by inputting text.

All of these actions require a physical device. Input devices range from the common - keyboards,